1. Field of the Invention
This invention relates generally to a television receiver, and more particular to such a television receiver of the projection type which projects an image formed on the cathode ray tube used in the television receiver onto a viewing screen.
2. Description of the Prior Art
A television receiver of the projection type is known in the prior art. However, the image projection system in the prior art can use only a viewing screen with a flat plane.
Generally, a light beam from the projector is projected onto a screen with an angle of elevation for avoiding an obstruction of the viewing field caused from the projector. In this case the projected raster on the screen has a trapezoid-shaped distortion, but this distortion can be compensated for relatively easily.
But, in the case where a concave screen is used for coinciding a focal plane and for increasing the brightness of the projected picture, the projected picture on the screen has a complex raster distortion and this distortion can't be compensated for easily.